Income Taxes (Schedule Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Net operating loss carryforward	$ 64	$ 70
Credit carryforward	26	24
Accruals	53	67
Pension	79	114
Allowance for doubtful accounts	5	12
Inventories	11	13
Other	15	36
Deferred taxes assets—total	253	336
Property, plant and equipment	(906)	(1,374)
Intangibles	(154)	(221)
Turnaround costs	(8)	(1)
Basis difference—consolidated partnerships	(209)	(308)
Other	(18)	(17)
Deferred tax liabilities—total	(1,295)	(1,921)
Valuation allowance	(56)	(53)
Total net deferred tax liabilities	(1,098)	(1,638)
Balance sheet classifications
Noncurrent deferred tax asset	13	12
Noncurrent deferred tax liability	$ (1,111)	$ (1,650)